/* Type definitions for the finite state machine for Bison.
Copyright (C) 2001-2007, 2009-2012 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include "system.h"
#include <hash.h>
#include "complain.h"
#include "gram.h"
#include "state.h"
#include "print-xml.h"
/*-------------------.
| Shifts and Gotos. |
`-------------------*/
/*-----------------------------------------.
| Create a new array of NUM shifts/gotos. |
`-----------------------------------------*/
static transitions *
transitions_new (int num, state **the_states)
{
size_t states_size = num * sizeof *the_states;
transitions *res = xmalloc (offsetof (transitions, states) + states_size);
res->num = num;
memcpy (res->states, the_states, states_size);
return res;
}
/*-------------------------------------------------------.
| Return the state such that SHIFTS contain a shift/goto |
| to it on SYM. Abort if none found. |
`-------------------------------------------------------*/
state *
transitions_to (transitions *shifts, symbol_number sym)
{
int j;
for (j = 0; ; j++)
{
aver (j < shifts->num);
if (TRANSITION_SYMBOL (shifts, j) == sym)
return shifts->states[j];
}
}
/*--------------------.
| Error transitions. |
`--------------------*/
/*---------------------------------.
| Create a new array of NUM errs. |
`---------------------------------*/
errs *
errs_new (int num, symbol **tokens)
{
size_t symbols_size = num * sizeof *tokens;
errs *res = xmalloc (offsetof (errs, symbols) + symbols_size);
res->num = num;
memcpy (res->symbols, tokens, symbols_size);
return res;
}
/*-------------.
| Reductions. |
`-------------*/
/*---------------------------------------.
| Create a new array of NUM reductions. |
`---------------------------------------*/
static reductions *
reductions_new (int num, rule **reds)
{
size_t rules_size = num * sizeof *reds;
reductions *res = xmalloc (offsetof (reductions, rules) + rules_size);
res->num = num;
res->lookahead_tokens = NULL;
memcpy (res->rules, reds, rules_size);
return res;
}
/*---------.
| States. |
`---------*/
state_number nstates = 0;
/* FINAL_STATE is properly set by new_state when it recognizes its
accessing symbol: $end. */
state *final_state = NULL;
/*------------------------------------------------------------------.
| Create a new state with ACCESSING_SYMBOL, for those items. Store |
| it in the state hash table. |
`------------------------------------------------------------------*/
state *
state_new (symbol_number accessing_symbol,
size_t nitems, item_number *core)
{
state *res;
size_t items_size = nitems * sizeof *core;
aver (nstates < STATE_NUMBER_MAXIMUM);
res = xmalloc (offsetof (state, items) + items_size);
res->number = nstates++;
res->accessing_symbol = accessing_symbol;
res->transitions = NULL;
res->reductions = NULL;
res->errs = NULL;
res->state_list = NULL;
res->consistent = 0;
res->solved_conflicts = NULL;
res->solved_conflicts_xml = NULL;
res->nitems = nitems;
memcpy (res->items, core, items_size);
state_hash_insert (res);
return res;
}
state *
state_new_isocore (state const *s)
{
state *res;
size_t items_size = s->nitems * sizeof *s->items;
aver (nstates < STATE_NUMBER_MAXIMUM);
res = xmalloc (offsetof (state, items) + items_size);
res->number = nstates++;
res->accessing_symbol = s->accessing_symbol;
res->transitions =
transitions_new (s->transitions->num, s->transitions->states);
res->reductions = reductions_new (s->reductions->num, s->reductions->rules);
res->errs = NULL;
res->state_list = NULL;
res->consistent = s->consistent;
res->solved_conflicts = NULL;
res->solved_conflicts_xml = NULL;
res->nitems = s->nitems;
memcpy (res->items, s->items, items_size);
return res;
}
/*---------.
| Free S. |
`---------*/
static void
state_free (state *s)
{
free (s->transitions);
free (s->reductions);
free (s->errs);
free (s);
}
/*---------------------------.
| Set the transitions of S. |
`---------------------------*/
void
state_transitions_set (state *s, int num, state **trans)
{
aver (!s->transitions);
s->transitions = transitions_new (num, trans);
}
/*--------------------------.
| Set the reductions of S. |
`--------------------------*/
void
state_reductions_set (state *s, int num, rule **reds)
{
aver (!s->reductions);
s->reductions = reductions_new (num, reds);
}
int
state_reduction_find (state *s, rule *r)
{
int i;
reductions *reds = s->reductions;
for (i = 0; i < reds->num; ++i)
if (reds->rules[i] == r)
return i;
return -1;
}
/*--------------------.
| Set the errs of S. |
`--------------------*/
void
state_errs_set (state *s, int num, symbol **tokens)
{
aver (!s->errs);
s->errs = errs_new (num, tokens);
}
/*--------------------------------------------------.
| Print on OUT all the lookahead tokens such that S |
| wants to reduce R. |
`--------------------------------------------------*/
void
state_rule_lookahead_tokens_print (state *s, rule *r, FILE *out)
{
/* Find the reduction we are handling. */
reductions *reds = s->reductions;
int red = state_reduction_find (s, r);
/* Print them if there are. */
if (reds->lookahead_tokens && red != -1)
{
bitset_iterator biter;
int k;
char const *sep = "";
fprintf (out, " [");
BITSET_FOR_EACH (biter, reds->lookahead_tokens[red], k, 0)
{
fprintf (out, "%s%s", sep, symbols[k]->tag);
sep = ", ";
}
fprintf (out, "]");
}
}
void
state_rule_lookahead_tokens_print_xml (state *s, rule *r,
FILE *out, int level)
{
/* Find the reduction we are handling. */
reductions *reds = s->reductions;
int red = state_reduction_find (s, r);
/* Print them if there are. */
if (reds->lookahead_tokens && red != -1)
{
bitset_iterator biter;
int k;
xml_puts (out, level, "<lookaheads>");
BITSET_FOR_EACH (biter, reds->lookahead_tokens[red], k, 0)
{
xml_printf (out, level + 1, "<symbol>%s</symbol>",
xml_escape (symbols[k]->tag));
}
xml_puts (out, level, "</lookaheads>");
}
}
/*---------------------.
| A state hash table. |
`---------------------*/
/* Initial capacity of states hash table. */
#define HT_INITIAL_CAPACITY 257
static struct hash_table *state_table = NULL;
/* Two states are equal if they have the same core items. */
static inline bool
state_compare (state const *s1, state const *s2)
{
size_t i;
if (s1->nitems != s2->nitems)
return false;
for (i = 0; i < s1->nitems; ++i)
if (s1->items[i] != s2->items[i])
return false;
return true;
}
static bool
state_comparator (void const *s1, void const *s2)
{
return state_compare (s1, s2);
}
static inline size_t
state_hash (state const *s, size_t tablesize)
{
/* Add up the state's item numbers to get a hash key. */
size_t key = 0;
size_t i;
for (i = 0; i < s->nitems; ++i)
key += s->items[i];
return key % tablesize;
}
static size_t
state_hasher (void const *s, size_t tablesize)
{
return state_hash (s, tablesize);
}
/*-------------------------------.
| Create the states hash table. |
`-------------------------------*/
void
state_hash_new (void)
{
state_table = hash_initialize (HT_INITIAL_CAPACITY,
NULL,
state_hasher,
state_comparator,
NULL);
}
/*---------------------------------------------.
| Free the states hash table, not the states. |
`---------------------------------------------*/
void
state_hash_free (void)
{
hash_free (state_table);
}
/*-----------------------------------.
| Insert S in the state hash table. |
`-----------------------------------*/
void
state_hash_insert (state *s)
{
if (!hash_insert (state_table, s))
xalloc_die ();
}
/*------------------------------------------------------------------.
| Find the state associated to the CORE, and return it. If it does |
| not exist yet, return NULL. |
`------------------------------------------------------------------*/
state *
state_hash_lookup (size_t nitems, item_number *core)
{
size_t items_size = nitems * sizeof *core;
state *probe = xmalloc (offsetof (state, items) + items_size);
state *entry;
probe->nitems = nitems;
memcpy (probe->items, core, items_size);
entry = hash_lookup (state_table, probe);
free (probe);
return entry;
}
/*--------------------------------------------------------.
| Record S and all states reachable from S in REACHABLE. |
`--------------------------------------------------------*/
static void
state_record_reachable_states (state *s, bitset reachable)
{
if (bitset_test (reachable, s->number))
return;
bitset_set (reachable, s->number);
{
int i;
for (i = 0; i < s->transitions->num; ++i)
if (!TRANSITION_IS_DISABLED (s->transitions, i))
state_record_reachable_states (s->transitions->states[i], reachable);
}
}
void
state_remove_unreachable_states (state_number old_to_new[])
{
state_number nstates_reachable = 0;
bitset reachable = bitset_create (nstates, BITSET_FIXED);
state_record_reachable_states (states[0], reachable);
{
state_number i;
for (i = 0; i < nstates; ++i)
{
if (bitset_test (reachable, states[i]->number))
{
states[nstates_reachable] = states[i];
states[nstates_reachable]->number = nstates_reachable;
old_to_new[i] = nstates_reachable++;
}
else
{
state_free (states[i]);
old_to_new[i] = nstates;
}
}
}
nstates = nstates_reachable;
bitset_free (reachable);
}
/* All the decorated states, indexed by the state number. */
state **states = NULL;
/*----------------------.
| Free all the states. |
`----------------------*/
void
states_free (void)
{
state_number i;
for (i = 0; i < nstates; ++i)
state_free (states[i]);
free (states);
}